The wrap disclosed in the wrap PCT application is formed from an elongate piece of woven polyester (or similar non-absorbable bio-stable and bio-compatible material). When laid on a planar surface, the wrap is substantially flat or planar. The wrap includes an opening for a fluid tube to be connected to the inflatable balloon or chamber of a heart assist device. The wrap also includes a thinned portion with a pair of curved longitudinal slits which assist in preventing the wrap from kinking, folding or pleating in the thinned portion when wrapped around a curved portion of an aorta.
Parts of the side of the wrap disclosed in the wrap PCT application have a series of spaced apart slits, which are substantially normal to the longitudinal axis of the wrap. The purpose of the slits is to make those parts of the wrap sides more elastic or stretchable than the intermediate central portion of the wrap. As a result, when the wrap disclosed in the wrap PCT application is placed around a curved arterial vessel, such as an ascending aorta, and tightened to a snug fit, less tension is placed in the sides or edges of the wrap than in the centre. This avoids the depression/kinking, and associated high strain levels, associated with earlier wraps without such slits.